tracking a z4

B

bazpro88

Member
hi all had my z for a few month and finally got round to doing a trackday last week at teeside autodrome. its only down the road and though why not.
on the road the z feels spot on . its a 3.0 manual , bilstien front shocks and lowered on eibach springs with some bbs ch reps.
on the track it felt like a barge ! wasn't very sharp to turn in and kept spinning the inside wheel coming out of the tight corners ( did get a sliding sometimes though :D )
anymore worthwhile mods to make it a bit better on track?
I understand tyres are probs going to be my next thing to change and ive had tracking done but thinking full on alinement may make it better.
also does anywhere do quickshifts for them and are they worth it.
it also felt even with the traction control fully off it still felt like it was holding it back.
bit of a rant I know but just want more out of it.
 
Any reason you've not replaced the rear shocks?

Best mod for track is tuition.
LSD for getting the power down along with better rubber.
New bushings will probably help as I assume they've not been done, poly ARB bushings, RTABs etc. as a start.
 
Firstly, good for you for doing a trackday in the first place, brilliant fun and the best way to learn how to drive your car properly IMO.

When you say the car isn't very sharp to turn in, is this because the front end is sliding, more steering lock than you expected, squeeling tyres...? Geometry will help (toe and camber), as would tyres (what are you running?), maybe the front end is too stiff relative to the rears and did you check and adjust the tyre pressures after you had been out on track?
I believe you have 2 stages to turning the safety systems off, first press is traction control off, the second is the stability control, were you pressing and holding the button down for that second stage? If so this should switch everything off.
Without a limited slip diff it is quite normal to spin up an inside wheel with a heavy foot. Next time out on track it is well worth booking a session or two with an experienced instructor who will give you some pointers, once happy with your driving it's worth discussing and practising trail braking where it is safe to do so; this will make the car more willing to turn in to the corner, but read up about this first as you don't want to be spinning.

trailing-brakes-drawing-Scott-Mansell.jpg


I can't help you about a short shift but personally I would put this low on your list.

More info will definitely help us give you advice, cheers, Dave
 
hard to explain about the steering it just doesn't seem responsive.
I never even looked at tyre pressures so theres a start straight away, got 255,35,18 continentals on the rear which have been superb on the road and only a few month old.
fronts are 225,40,18 roadstones or something, again a few month old and been fine on the road but am guessing they are really for track days.

ive not replaced the rear shocks as they seem ok and already has a few poly bushes from the previous owner.
ive done a few trackdays in the past but not in the z so kind of know a little bit but by now means a expert, I do it more for a laugh not to really set lap times but just didn't really enjoy myself as the car also felt underpowered .
the track is really tight and twisty so it may be better suited to croft which is also local and fancy doing cadwell too.
think I may get alinement done and check tyre pressures for the next one.
what pressures seem to work best for track use?
 
Thanks for the info, it helps.

Agreed that a different circuit like Croft will likely suit the car better. We all do trackdays for fun and don't time, so these tips are to help you enjoy the day and minimise wear to your tyres. :thumbsup:

Having cheapie tyres on the front and more grippy, fresher rubber on the back will help explain why it doesn't want to turn in. If budget allows I would change the front tyres to match the rears, this will make a good bit of difference. Contis are perfectly ok for occasional track use, lasting well (at least they did on my M).

Start the day with normal road tyre pressures, go out and drive 4 or 5 laps at reasonable pace and then come into the pits and quickly check the hot tyre pressures, reducing them back down to standard pressures. On a warm day you'll be surprised how much the pressures rise, particularly on the left hand side at clockwise tracks and you may need to do this process again during the day. Just remember that as the tyres cool, for example when driving home the pressures will drop so pump them back up again before leaving the circuit.

Assuming your car has the camber pins still fitted (do a search on here) you can remove these which will give you a bit more negative front camber and then get your geometry adjusted.

Lastly, I'll repeat the advice of booking an instructor. You can explain to them the handling frustrations (if still there after changing the above) and after observing your driving they will be able to give you tips which will help as well as make you more confident, faster and safer. Can't recommend instruction enough. :)
 
im surprised all the forum bashers aint along to tell you how you have now ruined your car.....lol

I'll add my bit im no track guru but do like a bit of fun. I managed to track mine a few times this year it handled well but could be better this is mainly down to not having coilovers fitted I think. A lot of people seem to think this bilstein/eibach setup is some must do mod its all I read on forums before buying one. I had the KW suspension if that makes any odds but tracking other cars before with coilovers there's no match. Thing is with all this copy the next man stuff is you never really get to hear what other brands are like and everyone will repeat some old stuff about bilstein/eibach time and time again like new parts don't come out. The rear trailing arm bushings effect the car a lot if there worn in theory the front wheels follow so will always be pushing and pulling the car off line and wont feel great as you mentioned. Many of these cars are old now and been tinkered by many past owners thinking they know best when all there doing is sometimes making the car worse by modifying some parts. Even the alloys you use for track will affect ride many track alloy brands like BBS and TSW etc are very light. I had CSL replicas on my car when I bought it and they were awful so I fitted my beyerns and tracked on them it was great. I had two sets a 18" and 19" set of beyerns the 19" had kumho 225/35/19 tyres and the 18" had yokohama paradas 225/35/18 both sets were square set up with 8.5J front and rear not wider setup. It supposed to counter the oversteer I don't know if that helps as I've never tracked any other Z4's. My next Z4 I will fit coilovers no doubt at all probably them BC fully adjustable coilovers with the adjustable damping settings approx £600. Last is deff tyre psi to much and you will feel lack of feel but too little and the car turns in horrible. I was using anthing from 28psi min to 34psi max
 
First question is what tyre pressures are you running?
Track use increases load on the tyre wall, standard pressures are too low to support the tyre with the weight transfer, track temp and surface make a difference too, as a rough guide next time increase your standard settings by 4psi then go up in 2psi steps until you either eliminate/reduce to tolerable levels the understeer and lack of turn in , or until the front starts to feel light, you can then play about + or - until you have a setting suitable for the corners on that particular track and conditions, what your looking for is good response and turn in over the lap average, you will have to compromise slow corners for fast as it's not possible to achieve best result for both , make a note of what you used and the temp that day.

Also bear in mind if you dial the tyres in well you will have to watch the temps and limit yourself to a few fast laps followed by one or two cool off laps

In Sprint and Hill climb competition there are classes for road going cars on road tyres, getting road tyres to work well is a matter of experience and experimentation, competition tyres have supportive side walls that transmit a lot of noise and vibration but give a far more stable tyre, road tyres are biased to low noise and ride quality with the downside of a soft pliable sidewall, so your suspension set up has to minimise weight transfer into the road tyre.

The inner rear wheel spinning up is a function of weight transfer coupled with no LSD, the weight is transferred from the inside to the out through the geometric roll centres and the anti roll bars (simple version), if you disconnect the rear anti roll bar (just unbolt one lower drop link and tie wrap it up) you will minimise this tendency and increase traction, but also increase understeer, so you have to dial the car in by making adjustments, a good starting point is rear bar disconnected then play with the tyre pressures to limit understeer. In the wet you can disconnect both front and rear bars.


The problem is you need a balanced spring set up, I have no idea what the likes of Eibach have specified in their springs, For competition use I calculate mine into CPM frequency and use 100-110cpm front and 120-130cpm rear, I also use adjustable dampers as this is a critical component in adjusting the transient behaviour of the car, adjust camber and toe settings with the use of a pyrometer and make up a set of adjustable anti roll bars.

This is not critical for track days but just gives you an idea how much variation there is just to get road tyres to work.
 
I always thought I would have to reduce tyre pressure for the track? that's what I do on bikes .
I never checked the pressures but 99% sure it will be about 30 psi as that's what they've always sat at.
to be fair it was really hot that day !!
I agree with the coilover thing, ive had a few cars with them on but always felt to harsh for the country roads up my way.
 
No you have to increase the pressure, your putting more load into the tyre so you require higher pressure to support it, think of how vague and unresponsive your car feels on the road with low pressure, on the track the extra load gives the same effect with standard road pressures!


My 325i Sport was (off the top of my head) 31f 33r for the road, on the track dependant on circuit we ran as high as 36f 38r, that was with yokohama 225 50 16,
 
Tyre pressures are a tricky one because weight of car, way you drive, type of tyre, geometry, type of corners and so much more will influence an ideal pressure. The nice thing is tyre pressures are easy to experiment with and are a free modification. I still stand by running standard pressures (when hot) to begin with, but it's not going to hurt to try 4psi higher either, it's good to experiment to see what works for you. I used to race at lower than standard pressures in the Caterham because I found that worked for me, but back when I used to sprint more road based cars at North Weald I always ran higher pressures. The important thing is that you are aware that pressures increase considerably with heat and as most circuits are clockwise in the UK this often results in the tyres on the left becoming hotter/higher pressure than those on the right, so adjust pressures after you've done a few laps.
Start with the small things like new front tyres, geometry, tyre pressures and some instruction and see how you find it. By all means chuck some money at the car on coilovers, but it's good to make a change and feel the difference. Hope to catch up with all you guys out on track sometime, want to see more Z4 in action. :driving:
 
goldbcfc said:
both sets were square set up with 8.5J front and rear not wider setup. It supposed to counter the oversteer
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For the umpteenth time a square setup reduces understeer not oversteer!
 
Steve84N said:
goldbcfc said:
both sets were square set up with 8.5J front and rear not wider setup. It supposed to counter the oversteer
Click to expand...
For the umpteenth time a square setup reduces understeer not oversteer!
Click to expand...

yeah I know u keep telling us from all your exp not using square setup on track yourself...... :thumbsdown:

thanks for forums hey and discussing things people actual do in the real world thanks for yet another lesson in square set up, were all using the wrong setup on track according to you from giving advice from your armchair get out there and try it then come back with your expert knowledge on the physics of engineering and racing.... :headbang:

people like you are the types to stand at the side and admire people like us which is real funny to me just like those annoying back seat drivers who aint even got a license telling you how to drive. In trade if someone tells you cant do it most times we'll try and find a way. If I don't have the right tool I will make a tool etc. Racing is all about trying new things and pushing boundaries or else no one would modify cars to make them better. Bmw has been know for years over engineering their cars you do realise that bmw does sell cars with square set up or did you think they all come with wider rears?
 
I'm always up for trying new things and finding what works for you and your car, but in this instance Steve is right that moving to a square set up is usually made to reduce understeer (not oversteer), as that extra rubber should help the front end grip. :)
 
Thank you Dave. :thumbsup:

Once again (goldie) you fly off the handle with the reply of a pillock. I said before that I agree a square setup is a good thing yet you still interpret me correcting you as an attack on your 'expertise'. You are so retarded at reading what people have actually said it's unreal. Not once did I give 'armchair advice' against your suggestion that it's good on track. Get your head out of your arse and behave. :headbang:
 
Lighten up chaps,



one thing to consider when putting larger tyres on rims is the sidewall angle, ideally an 8" tyre works best on an 8" rim, I know some guys who run 180/530/13 (7") on 8" rims but they are slicks which work very differently to road tyres.

The Z4 fronts are 225 (circa 9") on 8" rims, ok for the road but as far as you want to go really, putting tyres wider than this on an 8" rim can result in the sidewall deflecting leading to less grip and more carcass distortion.

Balancing the car is a tricky business that needs experience, if for instance you are suffering understeer ideally you want to increase front end grip, however there are times when this is impractical so you end up reducing rear end to balance the car, overall less grip but better balance and more confidence which equals quicker times as your not understeering off into the kitty litter or swapping ends with a car that suddenly steps out on you!

If you need to reduce oversteer then again disconnect the rear anti roll bar or increase rear tyre pressure, the bar transfers weight to the outside tyre increasing it's work whilst reducing the work done by the inside wheel, it's literally dumping more and more weight onto the tyre, a tyre can only take so much load before you distort the carcass and increase the slip angle, resulting in the back end stepping out.

Dave makes an interesting point which shows the variation in tyres when load is applied, I would be interested to know what tyres Dave was using, I used Avon's on a Westfield for hill climbs and ran sub 20psi for nearly all events, but that car weighed in at 610kg, his Caterham being half the weight of a Z4 could run with lower pressures, the benefit of this is it allows the tyre to move more generating heat, the more heat (up to a point) the more grip.

The problem for heavy cars is the tyre is already moving too much so you have to stabilise the tyre, generating heat is not a problem when your hurling 1300kg about, but as I mentioned above, get the tyres working well and overheating becomes an issue with road tyres as the tread blocks move about, any of you guys who have done a lot of track work will be familiar with the feel when your tyres go off!
 
Steve84N said:
Thank you Dave. :thumbsup:

Once again (goldie) you fly off the handle with the reply of a pillock. I said before that I agree a square setup is a good thing yet you still interpret me correcting you as an attack on your 'expertise'. You are so retarded at reading what people have actually said it's unreal. Not once did I give 'armchair advice' against your suggestion that it's good on track. Get your head out of your arse and behave. :headbang:
Click to expand...

^^ This. I am tired of wasting time reading long, attacking, factually all over the place rants.... I see the name and think "uh oh, here we go again for the tenth time" :thumbsdown:
 
Steve84N said:
Thank you Dave. :thumbsup:

Once again (goldie) you fly off the handle with the reply of a pillock. I said before that I agree a square setup is a good thing yet you still interpret me correcting you as an attack on your 'expertise'. You are so retarded at reading what people have actually said it's unreal. Not once did I give 'armchair advice' against your suggestion that it's good on track. Get your head out of your arse and behave. :headbang:
Click to expand...

It's not the first time I've mentioned using a square setup in threads and have said the whole reason we use square is for more front grip and on the more balance as the car feels better planted if you want to revisit those threads. I'm no track guru but I try and learn as I go along I don't sit at home watching F1 on the sofa taking notes id rather get out there and try things others have done and test them myself to give reviews. So if I've got the reducing oversteer or reducing understeer the wrong way around you still knew what I was getting at and the reason for using this setup it doesn't really doesn't matter now I will continue enjoying track with square set up anyway as I prefer that it gives me more confidence in corners and feels like I corner faster to me.
 
Artful-Bodger said:
Lighten up chaps,



one thing to consider when putting larger tyres on rims is the sidewall angle, ideally an 8" tyre works best on an 8" rim, I know some guys who run 180/530/13 (7") on 8" rims but they are slicks which work very differently to road tyres.

The Z4 fronts are 225 (circa 9") on 8" rims, ok for the road but as far as you want to go really, putting tyres wider than this on an 8" rim can result in the sidewall deflecting leading to less grip and more carcass distortion.

Balancing the car is a tricky business that needs experience, if for instance you are suffering understeer ideally you want to increase front end grip, however there are times when this is impractical so you end up reducing rear end to balance the car, overall less grip but better balance and more confidence which equals quicker times as your not understeering off into the kitty litter or swapping ends with a car that suddenly steps out on you!

If you need to reduce oversteer then again disconnect the rear anti roll bar or increase rear tyre pressure, the bar transfers weight to the outside tyre increasing it's work whilst reducing the work done by the inside wheel, it's literally dumping more and more weight onto the tyre, a tyre can only take so much load before you distort the carcass and increase the slip angle, resulting in the back end stepping out.

Dave makes an interesting point which shows the variation in tyres when load is applied, I would be interested to know what tyres Dave was using, I used Avon's on a Westfield for hill climbs and ran sub 20psi for nearly all events, but that car weighed in at 610kg, his Caterham being half the weight of a Z4 could run with lower pressures, the benefit of this is it allows the tyre to move more generating heat, the more heat (up to a point) the more grip.

The problem for heavy cars is the tyre is already moving too much so you have to stabilise the tyre, generating heat is not a problem when your hurling 1300kg about, but as I mentioned above, get the tyres working well and overheating becomes an issue with road tyres as the tread blocks move about, any of you guys who have done a lot of track work will be familiar with the feel when your tyres go off!
Click to expand...

I just read this after posting other comment. Sorry I get wound up easily by people who usually comment with expertise knowledge but never actually tried track etc. These are same types of people at work who come unstuck with all their great how to do things when you pass them the tools to actually do a job. He knew damn wel what I meant just finds it good to point score about who knows more about understeer/oversteer....... really?

I've noticed a lot I track with use quite high walled fat tyres, Ive used 225/35/18 and 225/35/19 tyres squeeled a lot on the 19" but had more grip it felt than using the 18" maybe that was just added weight of them I don't know. I tried 17" ot for track but on road and didn't like it. The car felt like it would wheel spin far to easy and turning into corners felt too light. Yet again maybe im to used to running 19" on my Z4
 
It's not the first time that you've been told either that it reduces understeer not oversteer (there's a pretty big difference between the 2 by the way), yet you still insist on aggressively telling us that we do not know what we are talking about and that you do. Stop it.
Quite why you post on a Z4 forum so much when you sold the car so long ago I don't really understand. I wouldn't mind except pretty much everything you say is nonsense and if anyone disagrees with you then you get aggressive. I can only presume you are banned from e46 forums so feel the need to vent your s**t here, please don't.
 
TomK said:
It's not the first time that you've been told either that it reduces understeer not oversteer (there's a pretty big difference between the 2 by the way), yet you still insist on aggressively telling us that we do not know what we are talking about and that you do. Stop it.
Quite why you post on a Z4 forum so much when you sold the car so long ago I don't really understand. I wouldn't mind except pretty much everything you say is nonsense and if anyone disagrees with you then you get aggressive. I can only presume you are banned from e46 forums so feel the need to vent you s**t here, please don't.
Click to expand...

+100
 
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